Internal combustion engine



April 24, 1934- H. P. RASMUSSEN 76 INTERNAL COMBUSTION ENGINE Filed July 18, 1952 1 25 Z 31 fmn n/ 5 T K/ 4 V 274726 Z fiaamaddew Patented Apr. 24, 1934- UNITED STATES PATENT I OFFICE 1 Claim.

This invention relates to improvement in internal combustion engines, and has reference more particularly to an improved construction of a two cycle engine.

The usual form of internal combustion engine employed in connection with automobiles is of the four cycle type. In this type of engine, there is an intake, a compression, a power and an exhaust stroke, so that there is only one power stroke for each two complete turns of the crank shaft by each cylinder, and therefore a four cycle, four cylinder internal combustion engine has the same number of impulses per revolution as a single cylinder steam engine.

Two cycle internal combustion engines are used for different purposes, but they are nearly all single cylinderand the gaseous fuel is compressed in the crank casing. Such engines are ordinarily employed for operating boats and similar machinery, but have not been adapted for use with automobiles or more complicated machines.

It is the object of this engine to produce a four cylinder internal combustion engine of the two cycle type that will have the same number of power impulses for each revolution of the crank shaft as is now obtained by means of the eight cylinder engines of the four cycle type.

This invention briefly described consists of an engine substantially like the ordinary internal combustion engine, but which has in addition to the usual power pistons and cylinders, auxiliary cylinders and co-operating pistons that are used to compress the gas and to deliver it to the power cylinders at predetermined points of their stroke. In one form a compression piston and cylinder are provided for each power piston and cylinder, and in another form one compression piston and cylinder is associated with each pair of power pistons and cylinders.

Having thus briefly described the invention and. its objects, the same will now be described in 'detail and for this purpose reference will be had to the accompanying drawing in which the preferred embodiment thereof has been illustrated and in which:

Fig. 1 is a vertical, longitudinal section through one form of this invention.

Fig. 2 is a vertical transverse section, taken on line 22 Fig. 1.

Fig. 3 is a side elevation, showing the intake -manifold and the manifold for distributing the compressed gasses to the power cylinders.

Fig. 4 is a section taken through the top of the engine on line 4-4 Fig. 3.

Fig. 5 is a longitudinal section similar to that shown in Fig. 1, but showing an engine in which 7 each power piston and cylinder is provided with a compression piston and cylinder for compressing the charge and delivering it; and

Fig. 6 is a diagram showing the angular relationship of the crank pins.

In the drawing, reference numeral 6 indicates an engine block which is provided with six cylinders that have been designated by reference nunaled in bearings 9 and 10 in the ends of crank case 11. The crank shaft is also provided with intermediate bearings 12 and 13. Located in each of the power cylinders is a piston 14, and in each of the compression cylinders a piston 15. The diameter of the several cylinders and pistons may be the same and the stroke is also the same for the power and the compression pistons, although this is not an essential feature. Connecting rods 16 extend from the various pistons to crank pins on the crank shaft in the manner shown in the drawing, and common to engines of this type. The engine block is provided with a water jacket 17 and has removable cylinder head 18 that is also provided with a water jacket space in the manner indicated in the drawing. The power cylinders have associated with them spark plugs 19, which are absent in the compression or pump cylinders.

Referring to Fig. 2, it will be seen that the engine block is provided on opposite sides with ports. The port designated by reference numeral 20 is the intake port, while that designated by reference numeral 21 is the exhaust port. The latter is in communication with an exhaust manifold 22. It will be noticed that the intake port is located lower than the outlet port, or exhaust port, and in practice the upper level of the intake port is practically at the same vertical point as the lower level of the exhaust port.

The lowermost side of the intake port opening usually corresponds with the top of the piston when itis in its lowermost position, as shown in Fig. 2. The pistons in the power cylinders are provided with transverse upwardly extending projections 23 that are curved on opposite sides, as shown in Fig. 2. These projections are located nearer to the intake than to the outlet port and serve to deflect the incoming gases upwardly so as to assist the scavenging of the cylinders at the time the charge is admitted. Referring to Fig. 4, it will be seen that the compression cylinders are provided each with a port opening 24, located at the very top of the cylinder. These openings are in communication with the manifold 25 whose lower end has two branches that extend laterally, and the end of each of these branches communicates with intake ports 20 of the power cylinders. A check valve 26 is provided between manifold 25 and the manifold 2'7, that is connected to the carburetor 28. By referring to Fig. 3, it will be seen that whenever either pistons move downwardly so as to produce a vacuum in the cylinders 7a, air will enter through the carburetor, as indicated by the arrow, and after mixing with the fuel in the usual manner will pass by the check valve 26 and enter the cylinder 7a, and when the piston 15 reverses, the charge within the compression cylinder will be compressed and will be delivered to the power cylinder at the proper time in the manner to be presently described. The two compression pistons are located 180 degres apart, so that they are always traveling in opposite directions at the same time.

The operation of the engine will now be described, and for this purpose reference will be hadto Figs. 1, 2, 3 and 4. In the construction shown in Fig. 1, the engine is practically a duplex one in which the two power cylinders at each end and the interposed compression cylinder, the pistons of which are connected with the crank shaft as indicated in Fig. 6, form an engine which is complete and which operates exactly the same as the corresponding parts at the other end, the difference between the two ends is that the corresponding pistons are oifset 180 degrees. For the purpose of this explanation the several cylinders have been indicated by letters A, B, C, D, E and F. We will assume that the crank shaft is rotating in a clockwise direction when viewed from the right hand and that the 'piston in cylinder A is moving downwardly and We will further assume that the charge in this cylinder has been ignited so that this is the power stroke. At the same instant the compression piston 15 in cylinder B is moving upwardly while the piston in cylinder C is at its lowermost point and has just received a charge which will be compressed on the upward stroke. The above operation is obtained by bending the crank shaft so that the crank pins for pistons A and B are spaced one hundred eighty degrees apart and are located directly opposite each other, while the crank pin for piston C is located so as to lag two hundred seventy degrees behind the crank pin for piston A, all as shown in Fig. 1. Since the pistons in cylinders D, E and F are connected to cranks that are located 180 degrees from those in the corresponding cylinders A, B, and C, the piston in cylinder D will be at the same height "as that in cylinder A and moving upwardly while the piston in cylinder E will be at the same height as that in cylinder B and moving downwardly, and the piston in cylinder F will beat thetop of its stroke and ready to commence the power stroke.

Let us now consider the operation of the engine with respect to cylinders A, B and C. The ignited charge in cylinder A, exerts pressure on the piston as this moves downwardly and while it moves to its lowermost position the piston in cylinder B will move upwardly, and at the same time the piston in cylinder C will be moving upwardly compressing a charge. Just before piston in cylinder A reaches a position like that shown in Fig. 2, the exhaust port 21 will be uncovered thereby permitting the burnt gases to fiow into the exhaust manifold and shortly afterwards the intake port 20 will be uncovered thereby permitting gases from the compression cylinder B to flow into the cylinder and displace the products of combustion which will be driven out through the exhaust port. The upwardly inclined side of the projection 23 directs the incoming gases upwardly so as to cause them to travel to the top of the cylinder and permit the burned gases to escape. As soon as the travel of the piston reverses, the intake port will be covered and shortly thereafter the outlet port will be covered and the gases will then be compressed for the remainder of the upward stroke. When the piston reaches the top of the stroke, after having compressed the gases, these are ignited by an electric spark plug 19, and the timing of the spark is effected by some well known timing mechanism which has not been described here because it forms no part of this invention. When the piston in cylinder C reaches the position shown in Fig. 2, a charge is delivered to it in the same manner as has just been described. It will be seen that the three cylinders A, B and C, with their power and compression pistons, form an operative engine and that these are supplemented by the pistons in cylinders D, E and F which operate exactly in the same way, but as above mentioned, are all spaced 180 degrees from the corresponding pistons in the other end, and therefore the engine produces one impulse from each power cylinder and each complete revolution of the crank shaft.

In the engine illustrated in Figs. 1 to 4, there is one compression cylinder for each pair of power cylinders and the engine block is therefore provided with six cylinders where there are four power cylinders employed.

In Fig. 5 a slightly modified form of construction has been shown. In this embodiment we have the same number of power pistons and cylinders, but each has associated with it a compression cylinder and piston, and therefore the entire engine is divided up into a number of independent two cycle engines, each having a power and a compression piston. When the construction shown in Fig. 5 is used, the compression cylinders and pistons may be smaller than those that are employed in the other embodiment. Except for the additional number of compression cylinders and pistons, the engine shown in Fig. 5 is the same as the one that has been described, and it is not believed that any further description is necessary. Attention is called, however, to the fact that in Fig. 5 the crank pins associated with the power and the compression pistons of each pair are placed 180 degrees apart and the power pistons are each placed 90 degrees from the nearest, the same as in the embodiment illustrated in Fig. 1.

From the above description, it will be seen that by combining with the four power cylinders of an engine, compression cylinders and pistons arranged in the manner above described and shown on the drawing, it is possible to obtain an engine having approximately twice the power of an ordinary fo-ur cycle, four cylinder engine of the same size.

Having described the invention what is claimed as new is:

An internal combustion engine of the two cycle type comprising, in combination an engine block having two spaced parallel power cylinders, a'

power piston in each cylinder, there being a compression pump cylinder located between the two power cylinders, a piston located in the compression cylinder, a crank shaft located below the cylinders, said shaft having a crank pin for each cylinder, connecting rods from each piston to a crank pin, the two crank pins to which the power pistons are connected being spaced 2'70 degrees apart and the crank pin for the compression piston being spaced 180 degrees from one of the power piston crank pins, the two power cylinders having each an intake port opening located so as to be completely uncovered when the piston reaches its lowermost point of travel, a conduit extending from the intake ports and connecting them with the upper end of the compression cylinder, the power pistons being longer than the stroke so that the intake ports will be uncovered only when the pistons are at their lowermost point of travel, a carbureter, a conduit having one end in communication with the carbureter and the other end in communication with the interior of the compression cylinder, and a one way valve between the compression cylinder and the carbureter which permits air and gas to travel from the carbureter to the cylinder but which prevents travel in the opposite direction.

HANS P. RASMUSSEN. 

